Feasibility of National Surveillance of Health-Care-Associated Infections in Home-Care Settings

This article examines the rationale and strategies for surveillance of health-care-associated infections in home-care settings, the challenges of nonhospital-based surveillance, and the feasibility of developing a national surveillance system

Tuberculosis screening by tuberculosis skin test or QuantiFERON-TB Gold In-Tube Assay among an immigrant population with a high prevalence of tuberculosis and BCG vaccination.

RationaleEach year 1 million persons acquire permanent U.S. residency visas after tuberculosis (TB) screening. Most applicants undergo a 2-stage screening with tuberculin skin test (TST) followed by CXR only if TST-positive at > 5 mm. Due to cross reaction with bacillus Calmette-Guérin (BCG), TST may yield false positive results in BCG-vaccinated persons. Interferon gamma release assays exclude antigens found in BCG. In Vietnam, like most high TB-prevalence countries, there is universal BCG vaccination at birth.Objectives1. Compare the sensitivity of QuantiFERON-TB Gold In-Tube Assay (QFT) and TST for culture-positive pulmonary TB. 2. Compare the age-specific and overall prevalence of positive TST and QFT among applicants with normal and abnormal CXR.MethodsWe obtained TST and QFT results on 996 applicants with abnormal CXR, of whom 132 had TB, and 479 with normal CXR.ResultsThe sensitivity for tuberculosis was 86.4% for QFT; 89.4%, 81.1%, and 52.3% for TST at 5, 10, and 15 mm. The estimated prevalence of positive results at age 15-19 years was 22% and 42% for QFT and TST at 10 mm, respectively. The prevalence increased thereafter by 0.7% year of age for TST and 2.1% for QFT, the latter being more consistent with the increase in TB among applicants.ConclusionsDuring 2-stage screening, QFT is as sensitive as TST in detecting TB with fewer requiring CXR and being diagnosed with LTBI. These data support the use of QFT over TST in this population

Mantoux tuberculin skin test (TST) and QFT-TB Gold In-Tube (QFT) response among participants, by tuberculosis group (rows) and three cutpoints for a positive TST (columns) at 5mm, 10mm, and 15mm induration.

<p>The area within a circle corresponds with the number of participants with a positive test; the area of the intersection of circles corresponds with the number of participants positive by both tests. </p

Figure 3

<div><p><b>Proportion positive QFT-TB Gold In-Tube (QFT) and Mantoux tuberculin skin test (TST) with positive at >5 mm induration (TST-5), >10 mm induration (TST-10), and >15 mm induration (TST-15) among four groups:</b> A) participants with chest radiographs not suggestive of TB (N=479); B) participants with chest radiographs suggestive of TB with negative sputum culture for TB (N=864); C) participants with chest radiographs suggestive of TB with positive sputum culture for TB (N=132); D) all U.S.-bound Vietnamese immigrant applicants (estimated).</p><p>*APC=annual percent change per year of age.</p></div